More particularly, the invention concerns, among such slides, those that comprise first and second runners and locking means to prevent or allow a relative longitudinal movement of the first and second runners, and in which:                the first runner comprises at least first and second notches, each notch being delimited longitudinally by a front edge and a rear edge,        the second runner comprises at least first and second cut-outs, each cut-out being delimited longitudinally by a front edge and a rear edge,        the locking means comprise a catch mounted on the second runner and having at least first and second teeth, the catch being able to be moved in a direction perpendicular to the longitudinal direction between a locked position in which the first and second teeth pass through the first and second cut-outs respectively to engage in the first and second notches to immobilize the first and second runners relative to one another, and an unlocked position in which the first and second teeth do not interact with the first and second notches of the first runner to allow the relative movement of the first and second runners.        
In this type of known slide, when the catch is in the locked position, the first and second teeth of the catch pass, with a degree of longitudinal clearance, through the cut-outs of the second runner to engage, also with longitudinal clearance, in the notches of the first runner.
Thus, even when the catch is in the locked position, the first and second runners undergo relative movements of a few millimetres or of a few tenths of millimetres, which is likely to cause inconvenience of use for the user when the latter is sitting on the vehicle seat.